mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

7 December

The picture below shows eight regular decagons. In each decagon, a red triangle has been drawn with vertices at three of the vertices of the decagon.
The area of each decagon is 240. What is the total area of all the red triangles?

Show answer

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2023

Advent calendar 2022

Advent calendar 2021

Advent calendar 2020


List of all puzzles

Tags

numbers rugby combinatorics averages odd numbers volume determinants shape functions pascal's triangle triangles parabolas factorials geometry taxicab geometry area products menace tournaments shapes clocks coins tangents polynomials bases geometric mean matrices cards differentiation money 2d shapes algebra doubling 3d shapes median pentagons sport multiplication palindromes colouring number folding tube maps symmetry speed axes chocolate elections even numbers games range christmas regular shapes probability routes surds probabilty proportion integers sets cubics dodecagons cryptic crossnumbers fractions calculus square numbers time gerrymandering trigonometry angles expansions remainders digital clocks binary multiples chess grids indices quadrilaterals perimeter consecutive numbers lines albgebra crosswords books digits the only crossnumber consecutive integers prime numbers graphs cube numbers arrows balancing star numbers quadratics integration means factors mean square roots ellipses ave polygons crossnumbers tiling logic perfect numbers digital products advent cryptic clues sequences sum to infinity unit fractions wordplay complex numbers spheres rectangles scales partitions sums dates circles decahedra triangle numbers dominos division coordinates chalkdust crossnumber people maths irreducible numbers hexagons crossnumber floors geometric means addition planes dice squares percentages

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2024